Does Semi-Rigid Instrumentation Using Both Flexion and Extension Dampening Spacers Truly Provide an Intermediate Level of Stabilization?

Table 1

Unilateral model (construct 1, 2, 3, and 4) adjacent level ROM and pressure. Brackets show which construct groups are significant.

	Intact	UF	UF + UT	UF + BT
	[1]	[2]	[3]	[4]
ROM (% of intact)
Flexion
L3-L4	Mean 100 (SD 23) [4]	Mean 101 (SD 20)	Mean 109 (SD 24)	Mean 111 (SD 27) [1]
L5-S1	Mean 100 (SD 32)	Mean 98 (SD 26)	Mean 107 (SD 41)	Mean 108 (SD 35)
Extension
L3-L4	Mean 100 (SD 11)	Mean 91 (SD 12)	Mean 101 (SD 16)	Mean 98 (SD 9)
L5-S1	Mean 100 (SD 26)	Mean 118 (SD 28)	Mean 133 (SD 43)	Mean 126 (SD 35)
Lateral bending
L3-L4	Mean 101 (SD 16)	Mean 98 (SD16) [3, 4]	Mean 105 (SD 17) [2]	Mean 106 (SD 20) [2]
L5-S1	Mean 100 (SD 28) [3,4]	Mean 104 (SD 29) [3, 4]	Mean 114 (SD 31) [1, 2]	Mean 116 (SD 31) [1, 2]
Axial rotation
L3-L4	Mean 100 (SD 31) [2,3,4]	Mean 89 (SD 29) [1, 3, 4]	Mean 93 (SD 28) [1, 2]	Mean 94 (SD 28) [1, 2]
L5-S1	Mean 100 (SD 22)	Mean 99 (SD 25)	Mean 110 (SD 27)	Mean 109 (SD 26)
Pressure; (% of intact)
Flexion
L3-L4	Mean 100 (SD 42) [4]	Mean 144 (SD 33)	Mean 166 (SD 38)	Mean 220 (SD 76) [1]
L5-S1	Mean 100 (SD 58) [3, 4]	Mean 141 (SD 62)	Mean 161 (SD 53) [1]	Mean 207 (SD 82) [1]
Extension
L3-L4	Mean 100 (SD 21)	Mean 74 (SD 26)	Mean 78 (SD 31)	Mean 99 (SD 24)
L5-S1	Mean 100 (SD 84)	Mean 103 (SD 78)	Mean 120 (SD 89)	Mean 113 (SD 96)
Lateral bending
L3-L4	Mean 100 (SD 54) [4]	Mean 97 (SD 59) [4]	Mean 109 (SD 66) [4]	Mean 127 (SD 76) [1, 2, 3]
L5-S1	Mean 100 (SD 78)	Mean 90 (SD 70)	Mean 90 (SD 65)	Mean 94 (SD 70)
Axial rotation
L3-L4	Mean 100 (SD 44)	Mean 92 (SD 33)	Mean 110 (SD 36)	Mean 81 (SD 21)
L5-S1	Mean 100 (SD 33)	Mean 85 (SD 35)	Mean 100 (SD 45)	Mean 87 (SD 33)